Application of soybean powder as urease enzyme replacement on EICP method for soil improvement technique

The applicability of bio-chemical grouting as the environmentally friendly and economically method for liquefaction remediation was evaluated. Several combinations of organic and in-organic precipitations methods were conducted to obtain the optimum grouting solution. Organic precipitation method employs a bio-agent of urease enzyme to dissociate urea into ammonium and carbonate ions. The produced carbonate ions are precipitated as calcite crystals in the presence of calcium ions. Meanwhile, the in-organic methods were performed using chemical compounds only, without the bio-agent. Unconfined compressive strength (UCS) tests were performed to evaluate the applicability of the grouting solutions for improving the soil strength. Grouting solution is injected into the prepared sand samples. The sand samples with a relative density of 50% were treated with one and two PV for 3-day curing times. The experimental results showed that the organic precipitation method produced the high precipitated amount and resulted in the significant improvement in the strength of the treated sand. The presence of the precipitated materials within the grains of soil generated the strength of 272 kPa. The results of this study have elucidated that the organic precipitation method composed of calcium chloride, magnesium sulfate, urea and enzyme of urease may be an alternative soil-improvement technique to prevent the liquefaction susceptibility.

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Penerapan Teknik Biocementation Oleh Bacillus Subtilis Dan Pengaruhnya Terhadap Permeabilitas Pada Tanah Organik

JURNAL SAINTIS ◽

10.25299/saintis.2020.vol20(01).4809 ◽

2020 ◽

Vol 20 (01) ◽

pp. 47-52

Author(s):

Firman Syarif ◽

Gian Mahadika Davino ◽

Muhammad Ferry Ardianto

Keyword(s):

Mechanical Properties ◽

Biological Activities ◽

Peat Soil ◽

Physical And Mechanical Properties ◽

Soil Improvement ◽

Infrastructure Development ◽

Calcite Precipitation ◽

Microbially Induced Calcite Precipitation ◽

Urease Enzyme ◽

Peat Area

(ID) Indonesia memiliki persentase area rawa dan gambut yang sangat besar. Kurang lebih 30% lahan di Indonesia adalah daerah rawa/gambut. Di Pulau Sumatera, Provinsi dengan lahan gambut terluas yaitu Provinsi Riau dengan luas ± 4, 04 juta Ha atau 56, 1% dari luas total lahan gambut di Sumatera. Siak merupakan salah satu kabupaten di Riau yang memiliki daerah gambut yang cukup luas. Keberadaan daerah gambut ini menyebabkan pengembangan infrastruktur di Desa Suak Merambai menjadi terhambat karena tingkat kesulitan yang tinggi dalam proses konstruksi di daerah rawa. Beberapa metode perbaikan tanah telah diterapkan pada tanah gambut berupa perbaikan tanah secara fisik, mekanis maupun kimia. Salah satu metode perbaikan tanah yang mulai berkembang saat ini adalah Bio Grouting. Bio Grouting telah dikembangkan sebagai teknologi perbaikan tanah baru yang sistem kerjanya seperti semen pada beton sehingga mampu mengikat partikel tanah melalui bantuan aktivitas biologi. Bio Grouting ini dapat meningkatkan sifat mekanik (kekuatan, kekakuan, kohesi, gesekan), menurunkan permeabilitas bahan berpori, memperkuat atau memperbaiki dan memodifikasi sifat fisik dan mekanik tanah. Sistem kerja Bio Grouting adalah pengendapan Calcite oleh induksi microbiology, microbially induced calcite precipitation (MICP), yang dilakukan oleh bakteri penghasil enzim urease. Teknik microbially induced calcite precipitation (MICP) / Bio Grouting ini akan coba diterapkan pada tanah gambut sehingga dapat memperbaiki sifat permeabilitas dari tanah gambut. Melalui penelitian ini diharapkan permasalahan kontruksi diatas tanah gambut dapat diminimalisir dan menjadi salah satu solusi yang ramah lingkungan yang bisa membantu pengembangan infrastruktur di Desa Suak Merambai Kecamatan Bungaraya Kabupaten Siak Provinsi Riau. (EN) Indonesia has a very large percentage of swamp and peat area. About 30% of the land in Indonesia is swamp / peat. On the island of Sumatra, the province with the most extensive peatlands is Riau Province with an area of ± 4, 04 million Ha or 56.1% of the total area of peatlands in Sumatra. Siak is one of the regencies in Riau which has quite extensive peat areas. The existence of this peat area causes the development of infrastructure in the Village of Suak Merambai to be hampered due to the high level of difficulty in the construction process in the swampy area. Several soil improvement methods have been applied to peat soils in the form of physical, mechanical or chemical soil improvements. One method of soil improvement that is starting to develop now is Bio Grouting. Bio Grouting has been developed as a new soil improvement technology that works like cement on concrete so that it can bind soil particles through the help of biological activities. Bio Grouting can improve mechanical properties (strength, stiffness, cohesion, friction), reduce permeability of porous materials, strengthen or improve and modify the physical and mechanical properties of the soil. The work system of Bio Grouting is the deposition of Calcite by induction of microbiology, microbially induced calcite precipitation (MICP), which is carried out by the bacteria producing the urease enzyme. This microbially induced calcite precipitation (MICP) / Bio Grouting technique will try to be applied to peat so as to improve the permeability of peat soil. Through this research, it is expected that construction problems on peatlands can be minimized and become one of the environmentally friendly solutions that can help infrastructure development in Suak Merambai Village, Bungaraya District, Siak Regency, Riau Province.

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